FIG. 1 depicts a portion of conventional perpendicular magnetic recording (PMR) head 10 as viewed from the air-bearing surface (ABS). The conventional PMR head 10 includes a conventional pole 16 and a top shield 24 separated by a write gap 20. Note that the top shield 24 also acts as pole during writing using the conventional PMR head 10. The conventional pole 16 and the top shield 24 are surrounded by insulating layers 18 and 22. The conventional pole 16 resides on a seed layer 12 and has sidewalls 14.
In conventional applications, the height of the conventional pole 16 is typically less than approximately three-tenths micrometer. The conventional pole 16 also has a negative angle such that the top of the conventional pole 16 is wider than the bottom of the conventional pole 16. Stated differently, the angle θ of the sidewalls is less than 90 degrees in the conventional pole 16 of FIG. 1. A pole having this height and shape is desirable for use in PMR applications.
FIG. 2 depicts a conventional method 50 for forming the conventional PMR head 10. A seed layer 12 for the conventional pole 16 is deposited and the pattern for the conventional pole 16 formed, via steps 52 and 54, respectively. The material for the conventional pole 16 is plated, via step 56. The remaining seed layer around the conventional pole 16 is removed, via step 58. The conventional pole 16 is then trimmed, via step 60. Consequently, the width of the conventional pole 16 and the negative angle are set in step 60. The insulator 18 is deposited around the conventional pole 16, via step 62. A chemical mechanical planarization (CMP) is performed to planarize the surface and expose the conventional pole 16, via step 64. The surface is planarized in order to allow subsequent processing to be performed as desired. The write gap 20 is provided, via step 66. The top shield 24 that also acts as the pole is deposited and patterned in step 68. Finally, the region around the top shield 24 is insulated, via step 70.
Although the conventional method 50 can be used to form a conventional PMR head 10, the variation in the CMP process used in exposing the conventional pole 16 in step 64 has a relatively large vertical variation. In particular, the three-sigma variation in the CMP is on the order of three-tenths micrometer. The variation in the CMP process is thus on the order of the height of the conventional pole 16. As a result, the height of the conventional pole 16 may be extremely difficult to control and fabrication of suitable conventional PMR heads 10 difficult to repeat. Manufacturing of conventional PMR heads 10 may, therefore, have a very low yield.
Accordingly, what is needed is an improved, repeatable method for fabricating a PMR head. The present invention addresses such a need.